Originally Posted by
Western Flyer
With all the minutia that is picked over in the bike world it would seem the 6% difference between 165 and 175 cranks might be a big enough deal.
It's not a 6% spread. The OP is 5'11", so rule out the smallest length and now he can choose between either a 170 or 175. If he can't make up his mind and the 172.5mm is available, then go with that and he'll be set. But he should be careful as to make sure his socks don't compress after peddling a while or that couple of mm will throw everything off.